I also agree: keep the molding and paint it the same color as the walls. I've seen examples of contemporary or modern furniture & decor working beautifully with that kind of treatment. I can't recall where exactly, but I'm pretty sure it was in one of Donald Kaufman's and Taffy Dahl's books on color/paint. The books are packed away somewhere, so I am relying on memory -- of an elaborate traditional room in a house in San Fransisco. The moldings were extremely ornate, and the whole room, walls + molding, was done in a soft grey or soft beige I think. The effect was stunning, and the room was a beautiful backdrop to the decor. Not only that, you'd be removing a valuable architectural part of your house (and an expensive one, as hosenemesis has pointed out) and, given the price of materials today, probably replacing it with molding of lesser-quality. Our former house was an Italianate Victorian, and the former owner "modernized" some rooms in it. Every time we priced out the cost of millwork to replace the missing or damaged molding and trim, I wanted to track down the former owner and bop him over the head with a two-by-four. We eventually sold that house, in a down market for full price, and one of the elements that the buyers found so appealing was the original trim. You simply cannot replace that kind of architectural element today. Well, you can, but it's going to cost you -- to really, really cost you.

We all started out knowing very little about anything. I was not being critical and apologize if I came across that way. What breckeyee said. Using stainless steel screws eliminates any rusting/discoloring. The old shingles will seal around the screws well enough to prevent water intrusion. That also allows the addition sections to be removeable if new shingles need to be installed.

Marisa - I almost hate to add to this. But, I am compelled, since I "restored" a 1900 Victorian home. "Restored" rather than "Remuddled"! haha! So, here's the deal. I hear you. You do not have to repair the wall behind the trim unless the cracking and crumbling extends past the 3" trim you want. Otherwise, the quick and dirty method is caulk around the window and fill any big openings with insulation if you can then place the new trim around window edge, nail in and hope you don't get more cracking or you could use contractors glue with minimal nailing, paint and final caulk. Simple, and I am not understanding your GCs not getting this easy process since you aren't restoring the original wood trim. Have you saved the trim, btw? It will bring some cash if you put it on Craig's list or other sales system, unless your GC has already "taken it of your hands"! Good luck. I wouldn't try to fix any cracking until you are done, because the installation will just cause more. Really depends on the condition of the original walls. Hope you get what you are looking for!

They are pretty simple to replace. They are easy to remove and easy to reproduce in most cases. This would be be a simple task for an experienced trim carpenter. Takes about 3 minutes to make one if you Making more than one And have the proper Equipment.